Prevalence, characteristics, and projection of long-term childhood cancer survivors in Sweden.

Population-level descriptions of long-term childhood cancer survivors are fundamental to survivorship care and research but seldom available. Accordingly, we aimed to describe long-term childhood cancer survivors at the population-level and project future prevalence. In this register-based study we calculated the absolute number and prevalence proportions of all individuals diagnosed with a childhood cancer (aged 0-14 years, 1958-2018) in Sweden who survived ≥ 5 years post-diagnosis and were alive and residing in Sweden on December 31st, 2023. We also described the clinical and sociodemographic characteristics of this population and presented the observed prevalence over time (1990-2023) and projected prevalence under different mortality assumptions (2024-2040). On December 31st, 2023, there were 8645 long-term childhood cancer survivors in Sweden, equivalent to nearly 1 in 1000 inhabitants (921 persons per million). Leukemias (28.3%) and central nervous system tumors (27.0%) were the most common childhood cancer diagnoses, although the distribution of cancer type varied by attained age. Disease burden in the preceding five years was heterogeneous: approximately 25-30% of the survivors had no recent diagnoses or prescriptions, while a similar proportion experienced substantial morbidity. Most adult survivors were employed (72.0%) and relatively few received sickness benefits (9.7%). From 1990 to 2023, the long-term survivor population tripled in size. Projected mean annual growth was between 1.6% and 2.2%, with the population increasing to approximately 11,400 - 12,600 individuals by 2040. As this heterogeneous population continues growing, our comprehensive description can help plan survivorship care and provide a benchmark for prevalence estimates in settings with less complete data.